Cherry Glen Picnic

Johnston, Saylorville Lake, Iowa

Tonight: low 61 °F, some dew, rain likely, breezy.

Nights by month

Night lows from 2016 to 2025: a typical night, and the cold one that comes 1 night in 10.

The mildest nights are in July, typically 68°F. The coldest are in January, when 1 night in 10 drops to -7°F. Frost is common in January, February, March, April, November and December.

Typical nightCold night (1 in 10)
  1. Jan17°F -7°FBag comfortable to -5°F · frost 97% · rain or snow 22% of days
  2. Feb19°F -4°FBag comfortable to -5°F · frost 91% · rain or snow 23% of days
  3. Mar31°F 21°FBag comfortable to 20°F · frost 54% · rain or snow 31% of days
  4. Apr41°F 28°FBag comfortable to 30°F · frost 17% · rain or snow 34% of days
  5. May53°F 42°FBag comfortable to 40°F · frost 0% · rain or snow 44% of days
  6. Jun65°F 57°FBag comfortable to 55°F · frost 0% · rain or snow 35% of days
  7. Jul68°F 62°FBag comfortable to 65°F · frost 0% · rain or snow 30% of days
  8. Aug66°F 59°FBag comfortable to 60°F · frost 0% · rain or snow 34% of days
  9. Sep (this month)61°F 52°FBag comfortable to 50°F · frost 0% · rain or snow 26% of days
  10. Oct47°F 33°FBag comfortable to 35°F · frost 9% · rain or snow 27% of days
  11. Nov33°F 20°FBag comfortable to 20°F · frost 47% · rain or snow 21% of days
  12. Dec24°F 7°FBag comfortable to 10°F · frost 86% · rain or snow 17% of days

| = 32°F

History: ERA5 and ERA5-Land reanalysis via Open-Meteo, corrected to the site's elevation. Bag rating: the comfort rating that keeps you warm in a tent on 9 of 10 nights that month.

Tonight

Worth a lookFriday, September 25, 10 p.m. to 7 a.m.

Warm enough at the coldest hour

Your selected gear looks warm enough

About 24 °F to spare at the coldest hour.

This is based on typical values for the gear types you picked, so treat it as an estimate.

  • Low outside61°F
  • Moisturesome dew, keep gear inside
  • Windgusty at times
  • Rainrain likely, keep everything under cover

Your night

  1. 10 p.m. until morningComfortableAir around you 68 to 63°F, some dew, gusty from 3 a.m., rain likely from 5 a.m. (up to 27 mph).
Every hour
  • 10 p.m.68°Fcomfortable, some dew
  • 11 p.m.67°Fcomfortable, some dew
  • midnight67°Fcomfortable, some dew, chance of rain
  • 1 a.m.66°Fcomfortable, some dew
  • 2 a.m.66°Fcomfortable, some dew
  • 3 a.m.65°Fcomfortable, some dew, gusty, chance of rain
  • 4 a.m.65°Fcomfortable, some dew, gusty, chance of rain
  • 5 a.m.64°Fcomfortable, some dew, rain likely
  • 6 a.m.64°Fcomfortable, some dew, rain likely
  • 7 a.m.63°Fcomfortable, some dew, gusty, rain likely

Times are local time at your spot (GMT-5).

What works tonight

The gear this night calls for, for someone who sleeps like you.

  • You have this

    Sleeping bag

    Comfort 60°F or colder

    Usually sold as a 51° bag. The number in a bag's name is the limit, not the comfort.

  • You have this

    Underneath you

    R1 or more

    The R-value says how well a pad keeps the cold ground out.

Before you sleep

  • Stake out every guyline and point the low, narrow end of the tent into the wind.
  • Rain is possible from about midnight. Keep the rain fly on and bring shoes and packs inside.
  • Bring shoes, clothes and electronics inside. Anything left out will be wet by morning.
How we estimated this

At the coldest hour (7 a.m.):

Outside at your spot
61°F
Warmth your shelter holds
+2 °F
Air around you
63°F
Your bag's comfort rating
39°F
Your comfort limit
39°F

24 °F to spare, so warm enough.

Assumptions

  • Bag categories use typical ratings as sold: summer about 50 °F (10 °C), 3-season about 30 °F (-1 °C), winter about 15 °F (-9 °C). The number in a bag's name is usually its lower limit, so its comfort rating is about 9 °F (5 °C) warmer.
  • What you lie on: foam mat about R2, thin air pad about R1.5, insulated pad about R3.5, winter pad R5 and up, van bed about R4, air mattress about R0.5. Colder ground needs a higher R-value.
  • Shelters hold a few degrees early in the night and less towards morning. Wind and clear, calm skies take warmth away.
  • Weather: Open-Meteo forecast for your spot, on a grid of a few kilometers, corrected to its height.
  • These are rules of thumb, not measurements. People and gear vary.

A forecast, not a promise. Mountains, valleys and water make their own weather, so trust what you see and feel on site. Terms and liability

Checked for a double-wall tent, a 3-season bag and a thin air pad. Check your own gear here.

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